Field
Embodiments disclosed herein generally relate to catwalks for conveying tubulars between a drill floor and a lower level of a drilling rig or drill site. Specifically, embodiments disclosed herein relate to a system and method for moving tubulars along the catwalk.
Description of the Related Art
In a drilling operation or rig work-over operation, whether on a water-based (offshore) or a land-based drilling rig, tubulars, such as drill pipe, risers, casing or other tubulars, are often stored at, or supplied from, a level that is below the drill floor. The tubulars must be transported to the drill floor from a storage location at the lower level and then may be transported back to the storage location from the drill floor. The tubulars may be transferred using equipment such as a gantry crane, a knuckle boom crane, a horizontal to vertical (HTV) arm, or a conveyor such as a “catwalk” to move the tubulars between the storage location and the drill floor, and vice versa. When using a catwalk, tubulars are typically mechanically transported (e.g. pushed and/or pulled) in a v-shaped trough, from the storage location below the rig floor to the rig floor, and vice versa.
Some tubulars, such as drill pipe, include threaded mating connections on opposing ends. One end of the drill pipe has a male (e.g., a “pin”) connection whilst the other has a female (e.g., a “box”) connection, and the end having the pin is typically the end that is pushed or pulled in the trough of the catwalk. The end having the box connection is typically lifted by an elevator or other lifting device during transfer of the pipe.
Sliding of the pin connection along the trough may damage the threads of the pin connection. Conventionally, thread protectors made of steel, plastic or other suitable material, are available. However, the protectors add additional costs and labor to the drilling operation when used. Additionally, while the trough provides some control of the tubulars in a pushing or pulling operation, the end of the tubular sliding in the trough is a “free end”. Thus, additional control of the end of the pipe with the pin connection is desired.
What is needed is a method and apparatus that provides control of the pin connection of tubulars.